Is this a Mk 5?

[rsingler]

Does anyone know what version of Mk 5 this is?
The ambient holes look like they have metal screens in them.
I haven't opened it up yet, but it looks to be a hybrid.
5-port turret and 3,000 psi yoke, but everything else looks much older.

Can anyone help me with this one? What's the purpose of the bulge around the ambient chamber?
More pics when I open it, if necessary to ID it.

 

[Fishpie]

Yes, it's a special cold water version of the MK5.
It has a wide waist with two holes that have what looks like small hollow port plugs. Under these, as you have discovered, are either small sintered filters or white plastic screens. These are here to help keep in the thick grease that is put in the ambient chamber to prevent freezing.

 

[underH2Oman]

Looks like the MK5 Environ early 70s it was the second generation MK5

 

[axxel57]

Yes, looks like the environmental version of the MK5.
The photo is from the SP Regulator Museum

 

[AfterDark]

It also looks to have to have the 3000psi yoke a mod made in the 80's I think when AL80's became popular. I had mine changed back then for that reason.

 

[redacted]

If you removed both plugs and screens, you could screw a tube of Scubapro Environmental Silicone into one of the openings to fill the chamber.

 

[rsingler]

Thanks, guys!